JP4751344B2 - Perpendicular magnetic recording medium and magnetic recording / reproducing apparatus - Google Patents

Description

  The present invention relates to a perpendicular magnetic recording medium and a magnetic recording / reproducing apparatus used in a hard disk device using magnetic recording technology.

  In recent years, as the capacity of hard disk drives has been increased, the recording bit size has become smaller as the recording density has increased. In order to form a large-capacity hard disk medium, it is necessary not only to reduce the recording bit size, but also to improve recording / reproduction characteristics, that is, to reduce noise generated from the medium. It is considered that the main cause of the medium noise is due to the zigzag domain wall at the bit boundary. One method for reducing noise generated from the bit boundary is to form a clearer recording bit boundary. As a result, the magnetic interaction between the recording bits is reduced, and recording and reproduction can be accurately performed on each recording bit.

  As a means for improving the recording / reproduction characteristics, for example, in a perpendicular magnetic recording medium in which at least a nonmagnetic underlayer, a magnetic layer, and a protective film are sequentially laminated on a nonmagnetic substrate, the magnetic layer includes ferromagnetic crystal grains. It consists of a nonmagnetic grain boundary mainly composed of oxide, and the nonmagnetic underlayer is composed of a hexagonal close-packed crystal structure metal or alloy, and between the nonmagnetic underlayer and the nonmagnetic substrate, There is a technique of providing a seed layer composed of a metal or alloy having a face-centered cubic crystal structure (see, for example, Patent Document 1). In particular, in this technique, the seed layer is a metal of any one of Cu, Au, Pd, Pt, and Ir, an alloy containing at least one of Cu, Au, Pd, Pt, and Ir, or an alloy containing Ni and Fe. It is characterized by being. This is to orient the (111) plane, which is the close-packed surface of the face-centered cubic structure, as a seed layer, and thereby orient the nonmagnetic underlayer consisting of the hexagonal close-packed structure formed on the (002) plane. Is possible. Thereby, the crystal orientation of the recording layer having the same hexagonal close-packed structure as the nonmagnetic underlayer is also improved, and a perpendicular magnetic recording medium having excellent magnetic properties can be obtained.

  However, when a crystalline seed layer having a face-centered cubic structure is used, the crystal orientation is improved. However, since the grain size of the seed layer is reflected in the nonmagnetic underlayer, it is difficult to refine the crystal grains. Become.

  Further, on the nonmagnetic substrate, at least a soft magnetic underlayer, a first nonmagnetic underlayer, a second nonmagnetic underlayer, a perpendicular magnetic recording film, and a protective film are provided. Since the base film is made of Pt, Pd or an alloy of at least one of them, and the second non-magnetic base layer is made of Ru or Ru alloy, there is a technique that tries to improve recording / reproduction characteristics and heat fluctuation resistance. (For example, refer to Patent Document 2). In particular, a Pt alloy or Pd alloy obtained by adding other elements to Pt or Pd can be used for the first undercoat film for the purpose of refining crystal grains. Preferred additive elements include B, C, P, Si, Al, Cr, Co, Ta, W, Pr, Nd, Sm, and the like. We are trying to improve the crystallinity of the formation and the magnetic recording layer.

However, by adding an additive to Pt or Pd, crystal orientation and recording / reproducing characteristics are improved. However, as in the example, the first nonmagnetic underlayer has a grain size observed, The shape of the particles is maintained. In this case, the particle size of the first nonmagnetic underlayer is limited, and it is difficult to further reduce the particle size of the magnetic recording layer.
JP 2003-77122 A JP 2004-327006 A

  The present invention has been made in view of the above circumstances, and aims to improve the orientation of magnetic particles in a perpendicular magnetic recording layer and to make the magnetic particles finer to obtain a perpendicular magnetic recording medium having good recording and reproducing characteristics. And

The perpendicular magnetic recording medium of the present invention comprises a nonmagnetic substrate,
At least one soft magnetic layer formed on a non-magnetic substrate;
Formed on the soft magnetic layer, having a fine crystal structure in which crystalline fine particles having a particle diameter of 1 to 3 nm are gathered, formed on the first Pd—Si layer and the first Pd—Si layer. A second Pd—Si layer having a Si content of less than 10 at%, wherein the Si content of the first Pd—Si layer is greater than the Si content of the second Pd—Si layer. A non-magnetic underlayer,
A second nonmagnetic underlayer made of ruthenium formed on the first nonmagnetic underlayer, and perpendicular magnetic recording containing Co and Pt as main components formed on the second nonmagnetic underlayer It is characterized by comprising a layer.

In addition, the magnetic recording / reproducing apparatus of the present invention has a fine crystal structure formed on the soft magnetic layer and in which crystalline fine particles having a particle diameter of 1 to 3 nm are collected, the first Pd—Si layer, A second Pd-Si layer formed on the first Pd-Si layer and having a Si content of less than 10 at%. The Si content of the first Pd-Si layer is A first nonmagnetic underlayer having a higher Si content than the Pd-Si layer, a second nonmagnetic underlayer made of ruthenium formed on the first nonmagnetic underlayer, and the second nonmagnetic underlayer A perpendicular magnetic recording medium comprising a perpendicular magnetic recording layer containing Co and Pt as main components formed on a base layer;
A mechanism for supporting and rotating the perpendicular magnetic recording medium;
A magnetic head having an element for recording information on the perpendicular magnetic recording medium and an element for reproducing recorded information;
And a carriage assembly that movably supports the magnetic head with respect to the perpendicular magnetic recording medium.

  According to the present invention, it is possible to improve the orientation of the magnetic particles in the perpendicular magnetic recording layer and make the magnetic particles finer to obtain a perpendicular magnetic recording medium having good recording / reproducing characteristics.

The perpendicular magnetic recording medium of the present invention comprises a nonmagnetic substrate,
One or more soft magnetic layers formed on a non-magnetic substrate;
A first nonmagnetic underlayer formed on the soft magnetic layer;
A second nonmagnetic underlayer formed on the first nonmagnetic underlayer; and a perpendicular magnetic recording layer formed on the second nonmagnetic underlayer.

  The first nonmagnetic underlayer has a fine crystal structure and is Pd or a Pd alloy.

  The second nonmagnetic underlayer is Ru or a Ru alloy.

  The fine crystal structure used in the present invention is an intermediate structure between a polycrystalline structure and an amorphous structure, in which the polycrystalline structure is further finely divided, for example, a collection of crystalline fine particles of about 1 to 3 nm. Point to.

  When the first nonmagnetic underlayer having such a fine crystal structure is formed, the second nonmagnetic underlayer and the perpendicular magnetic recording layer, which are formed on the first nonmagnetic underlayer and have the crystal structure, have the crystal grains of the first nonmagnetic underlayer. It can be formed more finely without being limited by the particle size of the nonmagnetic underlayer. In addition, since the first nonmagnetic underlayer is maintained in a microcrystalline state rather than amorphous, the second nonmagnetic underlayer can be improved in crystal orientation, and further, It is also possible to improve the orientation of the perpendicular magnetic recording layer to be formed.

  As described above, according to the present invention, by using the first nonmagnetic underlayer having a microcrystalline structure, the orientation of the perpendicular magnetic recording layer can be improved and the grain size can be reduced, and the recording / reproducing characteristics can be greatly improved. An improved perpendicular magnetic recording medium capable of high density recording can be obtained.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a sectional view schematically showing the configuration of a perpendicular magnetic recording medium according to an embodiment of the present invention.

  In FIG. 1, a perpendicular magnetic recording medium 10 includes a soft magnetic backing layer 2, a first nonmagnetic underlayer 3, a second nonmagnetic underlayer 4, a perpendicular magnetic recording layer 5, and a protection on a nonmagnetic substrate 1. The film | membrane 6 is laminated | stacked in order. Further, a lubricant layer (not shown) can be formed on the surface of the protective layer 6 by applying a lubricant such as perfluoropolyether by a dip method or the like.

  In the present invention, first, a soft magnetic backing layer is formed on a nonmagnetic substrate. By providing a soft magnetic backing layer having a high magnetic permeability, a so-called double-layer perpendicular magnetic recording medium having a perpendicular magnetic recording layer on the soft magnetic backing layer is formed. In this double-layer perpendicular magnetic recording medium, the soft magnetic underlayer causes a recording magnetic field from a magnetic head for magnetizing the perpendicular magnetic recording layer, for example, a single magnetic pole head, to flow in the horizontal direction to the magnetic head side. It plays a part of the function of the magnetic head, and can play a role of improving the recording and reproducing efficiency by applying a steep and sufficient perpendicular magnetic field to the recording layer of the magnetic field.

  As the soft magnetic material used for the soft magnetic underlayer, CoZrNb, CoTaZr, FeCoB, FeCoN, FeTaC, FeTaN, FeNi, CoB, FeAlSi, and the like having a high saturation magnetic flux density and good soft magnetic properties are used.

  The soft magnetic backing layer used in the present invention is a single layer or a laminate of two or more layers. In the case of a laminated body, an arbitrary nonmagnetic intermediate layer can be used between the soft magnetic layers.

  Next, a film to be the first nonmagnetic underlayer is formed on the soft magnetic backing layer. The first nonmagnetic underlayer is provided for the purpose of refining the crystal grains of the second nonmagnetic underlayer formed thereon and improving the crystal orientation of the crystal grains. The first nonmagnetic underlayer is formed from Pd or a Pd alloy. When a Pd alloy is used, it is preferably an alloy with at least one element selected from B, Hf, Si, Ti, Zr, Ge, Al, Cr, Mg, and V.

  More preferably, the first nonmagnetic underlayer is made of an alloy of Pd and Si.

  Here, a mixed material of Pd and Si is also included in one of the Pd alloys.

  The first nonmagnetic underlayer needs to have a fine crystal structure.

  Even if it is called a fine crystal structure, it shows a wide range of structures between a polycrystalline structure and an amorphous structure. However, the microcrystalline structure used in this application is a structure in which the polycrystalline structure is more finely divided. , Refers to a collection of crystalline fine particles of about 1 to 3 nm, including so-called granular structures (segregated granular microcrystals) in which amorphous segregates around fine particles. Not in. Further, when the fine crystal structure of the present application is measured by X-ray diffraction measurement, it is not detected as a clear peak structure, but lattice fringes can be clearly observed in a cross-sectional TEM structure or the like. In some cases, it can be observed as a large number of spots by electron beam diffraction or the like, unlike an amorphous ring shape.

  In the present invention, the first nonmagnetic underlayer made of Pd or Pd alloy having a microcrystalline structure having no crystal grain structure is used to remove the limitation due to the particle size of the first nonmagnetic underlayer, and the second The nonmagnetic underlayer and the perpendicular magnetic recording layer can be miniaturized. The same effect can be obtained even if an amorphous material having no particle structure is used, but the restriction due to the particle size of the first nonmagnetic underlayer can be removed. The improvement in the orientation of the nonmagnetic underlayer cannot be achieved at the same time. In the case of segregated granular microcrystals even if they are the same microcrystals, the grain size of the granular microcrystals is small, so that miniaturization is possible. Rather, it is different from the technology of the present application. Further, in this case, the degree of improvement in orientation is not inferior to that in the case of using a Pd polycrystalline underlayer having a face-centered cubic structure. On the other hand, when the first nonmagnetic underlayer having a microcrystalline structure is used as in the present invention, the orientation of the second nonmagnetic underlayer can be further improved as compared with the use of the underlayer having a Pd polycrystalline structure. it can. When a second nonmagnetic underlayer of Ru or Ru alloy is used on the first nonmagnetic underlayer having a Pd polycrystalline structure, epitaxial growth is performed from the first nonmagnetic underlayer to the second nonmagnetic underlayer. In this case, since there is a difference in lattice constant between the two underlying layers, a lattice relaxation layer (initial layer) for matching the lattice is generated. This lattice relaxation layer is likely to occur particularly in the second nonmagnetic underlayer made of Ru or Ru alloy. On the other hand, in the case of the first non-magnetic underlayer having a fine crystal structure used in the present invention, since the volume of the fine crystal is small, lattice strain is pushed into the fine crystal with reduced stress, and the lattice relaxation layer is It is formed on the first nonmagnetic underlayer side. Therefore, the orientation of the second nonmagnetic underlayer can be further improved as compared with the case where the Pd polycrystalline structure is used. Such an effect cannot be obtained with granular microcrystals.

  In order to obtain such a microcrystalline Pd film or Pd alloy film, for example, a part of the Pd film may be silicided. This can be achieved by forming a Pd or Pd alloy film in contact with a nonmagnetic seed layer made of Si or a Si compound. By forming the film in this way, the substrate side of the Pd, Pd alloy layer is silicided, and the Pd, Pd alloy layer on the recording layer side cannot maintain its particle size and is finely crystallized.

  Further, when a Pd—Si alloy is used as the first nonmagnetic underlayer, the first Pd—Si layer and the first Pd—Si alloy layer have different Pd and Si composition ratios. A stack of Pd—Si layers can be used. If necessary, a Pd—Si layer can be further laminated. In this case, since the first Pd—Si layer on the soft magnetic layer side functions as an Si supply layer, the Si content is the Si content of the second Pd—Si layer formed on the perpendicular magnetic recording layer side. More is preferred. When the Si composition amount of the Pd-Si film on the perpendicular magnetic recording layer side increases, the Pd-Si film becomes amorphous or segregated granular microcrystals, and it tends to be difficult to obtain an effect of improving the crystal structure. .

  The desirable Si composition amount of the second Pd—Si layer on the perpendicular magnetic recording layer side is less than 10 at%, more preferably 3 to 10 at%. If it exceeds 10 at%, the Pd—Si film is likely to be amorphous or segregated granular microcrystals, and it is difficult to obtain the effect of improving crystal orientation. In addition, if it is 3 at% or more, the effect of the microcrystal of the Pd—Si film is easily obtained.

  On the other hand, the Si content of the first Pd—Si layer on the soft magnetic layer side is preferably 10 at% or more, more preferably 10 to 100 at%. If it is less than 10 at%, the amount of Si supply decreases, and it becomes difficult to obtain microcrystals with the Pd—Si film on the perpendicular magnetic recording layer side. In addition, when the silicidation reaction is used, there is an advantage that the film can be flattened and the orientation can be improved more than in the case of normal film formation. This is unique to the silicidation reaction. Here, when a uniform single layer Pd—Si layer having no change in composition ratio is produced as the Pd—Si layer, a granular microcrystalline structure in which Si segregates around the Pd particles, or Pd— There is a tendency that the orthorhombic structure, which is the original structure of the Si film, or the crystal structure is not formed well and becomes amorphous. Further, the planarization effect peculiar to the silicidation reaction cannot be obtained, and therefore, it tends to be difficult to improve the orientation of the second nonmagnetic underlayer. On the other hand, a microcrystalline Pd—Si film can be obtained by stacking Pd—Si layers having different composition ratios as in the present invention. Further, in order to promote silicidation, when a film containing Pd or Si is formed, the film is preferably formed at a low pressure of about 0.5 Pa or less, more preferably about 0.3 to 0.05 Pa. Good. This prevents Si from being oxidized by impurities, thereby obtaining more active Si and promoting the silicide reaction. When this film is formed at a pressure of about 0.7 Pa, which is generally used, a part of Si is oxidized, so that the silicide reaction is suppressed and the Pd film or the Pd alloy film is not microcrystallized, or the segregated granular Pd alloy film. Tend to form. Note that the pressure described here is obtained by measuring the entire vacuum chamber used for film formation, but substantially indicates the degree of vacuum near the substrate. That is, sputtering is generally difficult to occur under a low pressure of 0.5 Pa or less, but in order to prevent this, only the pressure near the substrate is maintained using the differential exhaust method while keeping the pressure near the chamber and the target high. When lowered, the desired degree of vacuum mentioned above refers to the pressure near the substrate.

  The above-described action is unique to Pd and Pd alloys. For example, even when other materials such as Pt of the same platinum group are used, the effect of improving the crystal orientation is hardly seen. According to the present invention, the predetermined second nonmagnetic underlayer and the perpendicular magnetic recording layer are formed on the predetermined first nonmagnetic underlayer so that the recording / reproduction characteristics are good and the high density recording can be performed. A possible perpendicular magnetic recording medium can be obtained.

The second nonmagnetic underlayer has a function of transmitting the particle size and orientation of the laminated underlayer to the magnetic recording layer. It is important that the second nonmagnetic underlayer has an appropriate crystal matching with the first nonmagnetic underlayer and has a crystal plane on which the magnetic recording layer can be epitaxially grown. As such a material, Ru or Ru alloy having a hexagonal close-packed structure can be used on the surface of the second nonmagnetic underlayer. These materials have the advantage that the magnetic recording layer is easily grown epitaxially thereon. When a Ru alloy is used, it is preferably an alloy with at least one element selected from Cr, Co, Rh, C, SiO ₂ , TiO ₂ and Cr ₂ O ₃ . In particular, it is preferable to use an alloy with Cr.

Here, a mixed material of Ru and C, SiO ₂ , TiO _2, Cr ₂ O ₃ or the like is included in a part of the Ru alloy.

  By growing the perpendicular magnetic recording layer epitaxially on the second nonmagnetic underlayer, the fine and well-oriented crystal structure obtained in the underlayer can be introduced into the perpendicular magnetic recording layer. The perpendicular magnetic recording layer used in the present invention preferably contains Co and Pt as main components. Such a perpendicular magnetic recording layer has the advantages of relatively good crystal orientation and excellent thermal fluctuation resistance. In addition, two or more magnetic recording layers having different compositions can be stacked as the perpendicular magnetic recording layer. Moreover, you may put a heating / cooling process before and after film formation.

As a material constituting the perpendicular magnetic recording layer, for example, a CoPt alloy, a CoCr alloy, a CoCrPt alloy, a CoCrPtB alloy, a CoCrPtTa alloy, a CoCrPt—SiO ₂ alloy, a CoCrPtO alloy, a CoCrPt—TiO ₂ alloy, or the like can be used. Preferably, a CoCrPt—SiO ₂ alloy, a CoCrPtO alloy, or a CoCrPt—TiO ₂ alloy can be used. These alloys have the advantages of good crystal orientation, large magnetic anisotropy, and excellent resistance to thermal fluctuations. In the magnetic recording layer containing oxygen, the crystal grain boundary phase becomes clear, and the magnetic interaction can be further separated.

  At least one protective film can be provided on the perpendicular magnetic recording layer. Examples of the protective film include C, diamond-like carbon (DLC), SiNx, SiOx, CNx, and CHx.

  The soft magnetic underlayer, seed layer, underlayer, second nonmagnetic underlayer, perpendicular magnetic recording layer, and protective film can all be formed by various deposition techniques commonly used in the field of magnetic recording media. is there. Here, various sputtering methods are treated as one of the deposition techniques. As such a deposition technique, for example, a DC magnetron sputtering method, an RF magnetron sputtering method, or a vacuum deposition method can be used.

  When two or more kinds of substances are mixed, a unitary sputtering method using a composite target and a multi-source simultaneous sputtering method using targets of the respective substances can also be used.

  On the surface of the perpendicular magnetic recording medium, for example, the surface of the magnetic recording layer or the surface of the protective layer, a lubricant layer such as a perfluoropolyether may be applied by, for example, a dipping method or a spin coating method to form a lubricating layer. it can.

  FIG. 2 is a cross-sectional view schematically showing the configuration of the perpendicular magnetic recording medium according to one embodiment of the present invention.

  A perpendicular magnetic recording medium 20 shown in FIG. 2 includes a bias applying layer 7 such as an in-plane hard magnetic film and an antiferromagnetic layer, and a soft magnetic backing layer 2 between the soft magnetic backing layer 2 and the nonmagnetic substrate 1. Except that a nonmagnetic seed layer 8 is provided between the first nonmagnetic underlayer 3 and the first nonmagnetic underlayer 3, the structure is the same as that shown in FIG.

  The soft magnetic backing layer 2 is easy to form a magnetic domain, and spike-like noise is generated from this magnetic domain. Therefore, a bias applying layer 7 is provided and a magnetic field is applied in one radial direction to form a magnetic domain. A bias magnetic field can be applied to the formed soft magnetic underlayer 2 to prevent the occurrence of domain walls. It is also possible to make it difficult to form a large magnetic domain by finely dispersing the anisotropy with the bias applying layer 7 as a laminated structure.

The bias application layer material used for the bias application layer 7, CoCrPt, CoCrPtB, CoCrPtTa, CoCrPtC, CoCrPtCuB, CoCrRuB, CoCrPtWC, CoCrPtWB, CoCrPtTaNd, CoSm, CoPt, CoPtO, CoCrPtO, CoPt-SiO 2, and CoCrPtO-SiO ₂ is Can be mentioned.

  Any of the bias applying layers can be formed by a film forming method such as sputtering. A plurality of nonmagnetic layers may be formed between the substrate and the bias application layer in order to improve the crystallinity of the bias application layer or reduce the film thickness.

  Also, a nonmagnetic seed layer 8 made of Si or Si alloy can be formed between the soft magnetic backing layer 2 and the first nonmagnetic underlayer 3. When the nonmagnetic seed layer 8 made of Si alloy is formed so as to be in contact with the lower surface of the first nonmagnetic underlayer 3 made of Pd or Pd alloy, a silicide reaction occurs at the interface between Pd or Pd alloy and Si or Si alloy. And a Pd—Si compound phase is formed. By forming a Pd—Si compound phase under the Pd or Pd alloy layer, the Pd or Pd alloy layer is likely to become fine crystals.

  The metal used for the Si alloy of the nonmagnetic seed layer 8 is preferably at least one element selected from Zr, Hf, Ta, and Pd. These metals can easily form a metal silicide with Si, thereby forming a strong Pd—Si compound phase between the nonmagnetic seed layer and the first nonmagnetic underlayer.

  The preferred thickness of the nonmagnetic seed layer is 1 nm to 10 nm. If the thickness of the nonmagnetic seed layer is less than 1 nm, the uniformity of the composition in the in-plane direction of the nonmagnetic seed layer becomes insufficient, and the formation of the Pd—Si compound phase with the first nonmagnetic underlayer is not possible. There is a tendency to become insufficient. On the other hand, if the film thickness is greater than 10 nm, the distance from the magnetic head to the soft magnetic backing layer increases, and the recording / reproduction characteristics of the magnetic recording medium tend to deteriorate due to spacing loss. Further, heat treatment such as post-annealing may be performed in order to promote the formation of the metal silicide layer.

  Nonmagnetic substrates used in the present invention include Al-based alloy substrates such as aluminosilicate glass, chemically tempered glass, and AlMg substrates, and nonmagnetic substrates having higher heat resistance such as crystallized glass substrates, Si substrates, C substrates, A Ti substrate, a Si substrate with an oxidized surface, ceramics, plastic, or the like can be used. Furthermore, the same effect is expected even when the surface of these nonmagnetic substrates is plated with NiP alloy or the like.

  FIG. 3 is a partially exploded perspective view showing an example of the magnetic recording / reproducing apparatus of the present invention.

  As shown in FIG. 3, the perpendicular magnetic recording apparatus 30 of the present invention closes a rectangular box-shaped casing 31 having an upper opening and a top opening of the casing that is screwed to the casing 31 by a plurality of screws. And a top cover (not shown).

  In the casing 31, a perpendicular magnetic recording medium 32 according to the present invention, a spindle motor 33 as a driving means for supporting and rotating the perpendicular magnetic recording medium 32, and recording and reproduction of magnetic signals with respect to the magnetic recording medium 32 are performed. A magnetic head 34 to be performed; a head actuator 35 having a suspension having the magnetic head 34 mounted at the tip thereof and supporting the magnetic head 34 movably with respect to the perpendicular magnetic recording medium 32; and a rotary shaft for rotatably supporting the head actuator 35 36, a voice coil motor 37 that rotates and positions the head actuator 35 via the rotary shaft 36, a head amplifier circuit 38, and the like are housed.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Example Example 1
A nonmagnetic substrate made of a glass substrate for a 2.5 inch magnetic disk was prepared.

  This nonmagnetic substrate was placed in a vacuum chamber with a vacuum degree of 1 × 10 −5 Pa, and DC magnetron sputtering was performed as follows in an Ar atmosphere with a gas pressure of 0.7 Pa.

  First, a nonmagnetic substrate was disposed so as to face the target, and a CoCrPt ferromagnetic layer was formed using a CoCrPt target as a bias applying layer so that DC500W was discharged to the target to a thickness of 25 nm.

  A CoZrNb soft magnetic backing layer having a thickness of 120 nm was formed on the obtained CoCrPt ferromagnetic layer.

  Thereafter, on the CoZrNb soft magnetic underlayer, using a Si target as a nonmagnetic seed layer, discharge was performed at DC 500 W in an Ar atmosphere having a lower gas pressure of 0.1 Pa than usual, and a thickness of 5 nm was formed on the soft magnetic layer. As a result, the Si layer was formed.

  Next, as a first nonmagnetic underlayer, a Pd target is used and discharged at DC 500 W in an Ar atmosphere with a gas pressure of 0.1 Pa lower than usual so that the thickness is 5 nm on the Si seed layer. A Pd layer was formed by film formation.

  Here, the setting of the gas pressure during film formation was returned to the normal 0.7 Pa Ar atmosphere.

  Next, as a second nonmagnetic underlayer, a Ru target is used and discharged at 500 W DC to form a Ru layer on Pd first nonmagnetic underlayer so as to have a thickness of 20 nm. did.

Thereafter, a composite target of (Co-16 at% Pt-10 at% Cr) -8 mol% SiO ₂ is prepared on the second nonmagnetic underlayer, and CoPtCr—SiO _{2 is formed} on the Ru second nonmagnetic underlayer. A perpendicular magnetic recording layer was formed to a thickness of 15 nm.

  Finally, a C protective film was formed to 7 nm. After the substrate formed continuously in the vacuum container in this manner was taken out into the atmosphere, a perfluoropolyether-based lubricating film was formed to a thickness of 1.5 nm by a dip method to obtain a perpendicular magnetic recording medium. .

  The obtained perpendicular magnetic recording medium has a cross-sectional configuration similar to that of the perpendicular magnetic recording medium shown in FIG.

  When X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak and a CoCrPt (00.2) peak were observed, but a Pd (111) peak could not be observed. .

  When rocking curve measurement was performed on these peaks, the half-widths of the peaks were 2.5 ° (Ru) and 3.0 ° (CoCrPt), respectively.

  Thereby, it was found that the perpendicular magnetic recording layer had good crystallinity.

  Further, the obtained perpendicular magnetic recording medium was subjected to transmission analytical electron microscope (TEM) measurement in the cross-sectional direction to examine the crystal structure of the medium of the present invention. As a result, no crystal lattice fringes were observed in the Si seed layer, indicating that the Si seed layer was amorphous. On the other hand, in the Pd first nonmagnetic underlayer, crystal lattice stripes were clearly observed, but the direction was not uniform, and it was found that the Pd first nonmagnetic underlayer had a microcrystalline structure.

It was found that the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer had crystal lattice stripes arranged in an orderly manner in the direction perpendicular to the film surface and were epitaxially grown from the second nonmagnetic underlayer to the recording layer.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 4 to 6 nm.

  A magnetic field of 1185 A / m (15000 Oe) is applied to the obtained perpendicular magnetic recording medium radially outward of the substrate on the disk by using a magnetizing device equipped with an electromagnet, and the bias applying layer is made ferromagnetic. Magnetization in the in-plane radial direction of the layer was performed. Recording and reproduction characteristics of the magnetized perpendicular magnetic recording medium were evaluated using a read / write analyzer 1632 and spin stand S1701MP manufactured by GUZIK.

  As the recording / reproducing head, a single magnetic pole head was used as the recording element, and a head having a recording track width of 0.25 μm and a reproducing track width of 0.15 μm using the magnetoresistive effect as the reproducing element. Further, the measurement was performed at a constant position of a radial position of 22.2 mm from the center at a rotational speed of the disk of 4200 rpm. As a result, an excellent medium having an SNRm (reproduction signal output S: output at a linear recording density of 119 kFCI, Nm: rms value of noise measured when recording at 716 kFCI) (27.0 dB) can be obtained. I was able to.

Comparative Example 1
As a comparative perpendicular magnetic recording medium, the vertical direction of Example 1 was used except that the Si seed layer was not formed and the Pd first nonmagnetic underlayer was formed at a normal Ar pressure of 0.7 Pa. A perpendicular magnetic recording medium was obtained in the same manner as the magnetic recording medium.

  The obtained perpendicular magnetic recording medium has the same layer structure as that of the perpendicular magnetic recording medium shown in FIG. 2 except that there is no Si seed layer.

  Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak, a CoCrPt (00.2) peak, and a Pd (111) peak were observed.

  When rocking curve measurement was performed on the Ru and CoCrPt peaks, the half-widths of the peaks were 4.2 ° (Ru) and 5.1 ° (CoCrPt), respectively.

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, crystal lattice fringes were clearly observed in the first nonmagnetic underlayer of Pd, and the direction thereof was almost uniform in the direction perpendicular to the film surface.

Further, in the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer, crystal lattice stripes were regularly arranged in the direction perpendicular to the film surface.

  Thus, it was found that the first nonmagnetic underlayer was epitaxially grown from the Pd layer to the recording layer.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 8 to 14 nm.

  When the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 17.5 dB.

  As a result, the medium of the present invention of Example 1 in which the Si seed layer and the Pd first nonmagnetic underlayer were formed at a lower Ar pressure than the conventional medium of Comparative Example 1 had a perpendicular magnetic recording layer. It was found that the crystal grains were fine, the crystallinity was good, and the recording / reproduction characteristics were good.

Comparative Example 2
As a comparative perpendicular magnetic recording medium, perpendicular magnetic recording was performed in the same manner as the perpendicular magnetic recording medium of Example 1, except that the Si seed layer was not formed and Pt was used instead of Pd as the first nonmagnetic underlayer. A recording medium was obtained. The obtained perpendicular magnetic recording medium has no Si seed layer and the perpendicular magnetic recording shown in FIG. 2 except that the Pt first nonmagnetic underlayer is used instead of the Pd first nonmagnetic underlayer. It has the same layer structure as the medium.

  Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak, a CoCrPt (00.2) peak, and a Pt (111) peak were observed.

When rocking curve measurement was performed on the Ru and CoCrPt peaks,
The half widths of the peaks were 4.5 ° (Ru) and 5.5 ° (CoCrPt), respectively.

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, crystal lattice fringes were clearly observed in the first Pt nonmagnetic underlayer, and the direction was almost uniform in the direction perpendicular to the film surface.

Further, in the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer, crystal lattice stripes were regularly arranged in the direction perpendicular to the film surface. As a result, it was found that the first nonmagnetic underlayer was epitaxially grown from the Pt layer to the perpendicular magnetic recording layer.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 9 to 16 nm.

  When the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 15.5 dB.

  Therefore, the medium of the present invention of Example 1 in which the Si seed layer and the Pd first nonmagnetic underlayer are formed at a lower Ar pressure than the conventional medium of Comparative Example 2 is more perpendicular to the crystal of the perpendicular magnetic recording layer. It was found that the particles were fine and the crystallinity was good, and the recording / reproduction characteristics were good.

Comparative Example 4
As a comparative perpendicular magnetic recording medium, perpendicular magnetic recording of Example 1 except that the Si seed layer and the first nonmagnetic underlayer were formed by using Pt instead of Pd at a normal Ar pressure of 0.7 Pa. A perpendicular magnetic recording medium was obtained in the same manner as the medium.

  The obtained perpendicular magnetic recording medium has the same layer structure as that of the perpendicular magnetic recording medium shown in FIG. 2, except that the Pt first nonmagnetic underlayer is used instead of the Pd first nonmagnetic underlayer.

  Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak, a CoCrPt (00.2) peak, and a Pt (111) peak were observed.

When rocking curve measurement was performed on the Ru and CoCrPt peaks,
The half widths of the peaks were 4.7 ° (Ru) and 5.9 ° (CoCrPt), respectively.

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, no crystal lattice fringes were observed in the Si seed layer, indicating that the Si seed layer was amorphous.

  In the Pt first nonmagnetic underlayer, crystal lattice stripes were clearly observed, and the direction thereof was almost uniform in the direction perpendicular to the film surface.

Further, in the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer, crystal lattice stripes were regularly arranged in the direction perpendicular to the film surface. As a result, it was found that the first nonmagnetic underlayer was epitaxially grown from the Pt layer to the recording layer.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of approximately 10 to 15 nm.

  When the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 14.9 dB.

  As a result, the medium of the present invention of Example 1 in which the Si seed layer and the Pd first nonmagnetic underlayer were formed at a lower Ar pressure than the conventional medium of Comparative Example 4 had a perpendicular magnetic recording layer. It was found that the crystal grains were fine, the crystallinity was good, and the recording / reproduction characteristics were good.

Comparative Example 5
The perpendicular magnetic recording medium of Example 1 was used except that, as a comparative perpendicular magnetic recording medium, Pt was used instead of Pd as the Si seed layer and the first nonmagnetic underlayer, and was formed at 0.1 Pa with an Ar pressure lower than usual. A perpendicular magnetic recording medium was obtained in the same manner as the recording medium.

  The obtained perpendicular magnetic recording medium has the same layer structure as that of the perpendicular magnetic recording medium shown in FIG. 2, except that the Pt first nonmagnetic underlayer is used instead of the Pd first nonmagnetic underlayer.

  Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak, a CoCrPt (00.2) peak, and a Pt (111) peak were observed.

When rocking curve measurement was performed on the Ru and CoCrPt peaks,
The half widths of the peaks were 3.7 ° (Ru) and 3.9 ° (CoCrPt), respectively.

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined.

  As a result, no crystal lattice fringes were observed in the Si seed layer, indicating that the Si seed layer was amorphous.

  In the first nonmagnetic underlayer of Pt, crystal lattice stripes were clearly observed, but the direction was not uniform, and it was found that the Pt first nonmagnetic underlayer had a microcrystalline structure.

Further, in the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer, crystal lattice stripes were regularly arranged in the direction perpendicular to the film surface.

  As a result, it was found that epitaxial growth occurred from the second nonmagnetic underlayer to the recording layer.

Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. .
As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 7 to 11 nm.

  When the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 19.1 dB.

  Although the particle size is finer than that of other comparative examples, the improvement in orientation was insufficient.

  Therefore, the medium of the present invention of Example 1 in which the Si seed layer and the Pd first nonmagnetic underlayer were formed at an Ar pressure lower than that of the conventional medium of Comparative Example 5 was higher than that of the perpendicular magnetic recording layer. It was found that the particles were fine, the crystallinity was good, and the recording / reproduction characteristics were good.

Example 2
As the first nonmagnetic underlayer of the medium of the present invention, two types of targets having different composition amounts, a Pd-34 at% Si target (soft magnetic side), and a Pd-5 at% Si target (perpendicular magnetic recording layer side) were used. Prepared.

  Instead of Pd target as the first nonmagnetic underlayer, the above two types of Pd-Si target, Pd-34 at% Si target and Pd-5 at% Si target were used, except that the Si seed layer was not used. In the same manner as in Example 1, a perpendicular magnetic recording medium was produced.

  The obtained perpendicular magnetic recording medium is the same as the perpendicular magnetic recording medium shown in FIG. 2 except that there is no Si seed layer and two Pd—Si layers having different compositions are formed as the first nonmagnetic underlayer. It has the composition of.

FIG. 4 is a schematic cross-sectional view showing the configuration of the obtained perpendicular magnetic recording medium.
As shown in the figure, this perpendicular magnetic recording medium 50 includes a Pd-34 at% Si layer 19 as a CoCrPt ferromagnetic layer 17, a CoZrNb soft magnetic underlayer 12, and a first nonmagnetic underlayer 13 on a nonmagnetic substrate 11. And a Pd-5 at% Si layer 21, a Ru second nonmagnetic underlayer 14, a CoPtCr—SiO ₂ perpendicular magnetic recording layer 15, a C protective film 16, and a lubricating layer (not shown).

  X-ray diffraction measurement was performed on the medium of the present invention.

A Ru (00.2) peak and a CoCrPt (00.2) peak were observed, but a Pd (111) peak could not be observed.

  When rocking curve measurement was performed on these peaks, the half-widths of the peaks were 2.6 ° (Ru) and 3.2 ° (CoCrPt), respectively.

  Thereby, it was found that the perpendicular magnetic recording layer had good crystallinity.

  The obtained perpendicular magnetic recording medium was subjected to transmission analytical electron microscope (TEM) measurement in the cross-sectional direction to examine the crystal structure of the medium of the present invention. As a result, no clear crystal lattice stripes were observed in the Pd—Si first nonmagnetic underlayer on the soft magnetic layer side, and it was found to be amorphous.

  In the Pd—Si first nonmagnetic underlayer on the perpendicular magnetic layer side, crystal lattice fringes were clearly observed, but the direction was not uniform, and it was found to have a microcrystalline structure.

It was found that the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer had crystal lattice stripes arranged in an orderly manner in the direction perpendicular to the film surface and were epitaxially grown from the second nonmagnetic underlayer to the recording layer.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 5 to 7 nm.

  Further, when the recording / reproduction characteristics were evaluated in the same manner as in Example 1, it was found that the SNRm was 26.0 dB, and the characteristics were satisfactory.

Comparative Example 6
As a comparative perpendicular magnetic recording medium, the same as the perpendicular magnetic recording medium of Example 1 except that the Si seed layer was not formed and Pd-5 at% Si was formed instead of Pd as the first nonmagnetic underlayer. Thus, a perpendicular magnetic recording medium was obtained. The obtained perpendicular magnetic recording medium is the same as the perpendicular magnetic recording shown in FIG. 2 except that a Pd—Si first nonmagnetic underlayer is formed in place of the Pd first nonmagnetic underlayer and no Si seed layer is formed. It has the same layer structure as the medium.

  Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak and a CoCrPt (00.2) peak were observed, but a Pd (111) peak was observed. could not. When rocking curve measurement was performed on the Ru and CoCrPt peaks, the half-widths of the peaks were 5.0 ° (Ru) and 6.2 ° (CoCrPt), respectively.

A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, the Pd—Si first nonmagnetic underlayer was observed to have lattice fringes and was in a microcrystalline state, but the orientation of the microcrystal was random, and the film was uneven, and flatness was difficult. was there. On the other hand, from the Ru second nonmagnetic underlayer to the CoCrPt—SiO ₂ recording layer, crystal lattice stripes were aligned in the direction perpendicular to the film surface and epitaxially grown. However, from the Pd—Si first nonmagnetic underlayer to the Ru second nonmagnetic underlayer,
In particular, since epitaxial growth is not performed, variations in the growth direction and grain size are observed in the initial layer portion of the Ru second nonmagnetic underlayer. Therefore, the Ru second nonmagnetic underlayer and CoCrPt—SiO _A large particle size dispersion was observed in the particle size of the _two recording layers.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of approximately 7 to 17 nm.

  When the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 17.5 dB.

  As a result, the medium of the present invention of Example 2 has finer crystal grains in the perpendicular magnetic recording layer and better crystallinity than the conventional medium of Comparative Example 6, and good recording / reproduction characteristics. I found out that

Comparative Example 7
As a comparative perpendicular magnetic recording medium, the same as the perpendicular magnetic recording medium of Example 1, except that the Si seed layer was not formed and Pd-26 at% Si was formed instead of Pd as the first nonmagnetic underlayer. Thus, a perpendicular magnetic recording medium was obtained. The obtained perpendicular magnetic recording medium is the same as the perpendicular magnetic recording shown in FIG. 2 except that a Pd—Si first nonmagnetic underlayer is formed in place of the Pd first nonmagnetic underlayer and no Si seed layer is formed. It has the same layer structure as the medium.

  Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak and a CoCrPt (00.2) peak were observed, but a Pd (111) peak was observed. could not. When rocking curve measurement was performed on Ru and CoCrPt peaks, the half-widths of the peaks were 4.1 ° (Ru) and 5.1 ° (CoCrPt), respectively.

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, the Pd—Si first nonmagnetic underlayer had a segregated granular structure segregated at the Pd particles and the Si grain boundaries.

From the Pd—Si first nonmagnetic underlayer to the CoCrPt—SiO ₂ recording layer, it was found that lattice fringes were regularly arranged and epitaxially grown. However, unevenness was observed at the film interface, and flatness was difficult.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 7 to 10 nm.

  When the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 19.5 dB.

Thereby, the medium of the present invention of Example 2 is more preferable than the conventional medium of Comparative Example 7.
It was found that the crystal grains of the perpendicular magnetic recording layer are fine and have good crystallinity and good recording / reproducing characteristics.

Comparative Example 8
As a comparative perpendicular magnetic recording medium, except that the Si seed layer and the Ru second nonmagnetic underlayer were not formed, and Pd-26 at% Si was formed instead of Pd as the first nonmagnetic underlayer, A perpendicular magnetic recording medium was obtained in the same manner as the perpendicular magnetic recording medium of Example 1.

  In the obtained perpendicular magnetic recording medium, a Pd—Si first nonmagnetic underlayer was formed instead of the Pd first nonmagnetic underlayer, and no Si seed layer and Ru second nonmagnetic underlayer were formed. Has the same layer structure as that of the perpendicular magnetic recording medium shown in FIG. Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a weak CoCrPt (00.2) peak was observed.

  When rocking curve measurement was performed on the CoCrPt peak, the half-width of the peak was 10.1 ° (CoCrPt).

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, the Pd—Si first nonmagnetic underlayer had a segregated granular structure segregated at the Pd particles and the Si grain boundaries.

Lattice fringes were observed from the Pd—Si first nonmagnetic underlayer to the CoCrPt—SiO ₂ recording layer, indicating that epitaxial growth occurred. However, unevenness was observed at the film interface, and flatness was difficult.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the comparative medium was examined. As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of approximately 14 to 20 nm.

  Further, when the recording / reproducing characteristics were evaluated in the same manner as in Example 1, the SNRm was 3.8 dB.

From this, the medium of the present invention of Example 2 is more preferable than the conventional medium of Comparative Example 8.
It was found that the crystal grains of the perpendicular magnetic recording layer are fine and have good crystallinity and good recording / reproducing characteristics.

Comparative Example 9
As a comparative perpendicular magnetic recording medium, a perpendicular magnetic recording medium was obtained in the same manner as the perpendicular magnetic recording medium of Example 1 except that Pd-26 at% Si was formed instead of Pd as the first nonmagnetic underlayer. .

  The obtained perpendicular magnetic recording medium has the same layer structure as that of the perpendicular magnetic recording medium shown in FIG. 2 except that a Pd—Si first nonmagnetic underlayer is formed instead of the Pd first nonmagnetic underlayer. Have. Next, when X-ray diffraction measurement was performed on the obtained perpendicular magnetic recording medium, a Ru (00.2) peak and a CoCrPt (00.2) peak were observed, but a Pd (111) peak was observed. could not.

  When rocking curve measurement was performed on Ru and CoCrPt peaks, the half-widths of the peaks were 4.2 ° (Ru) and 5.7 ° (CoCrPt), respectively.

  A cross-sectional TEM measurement was performed on the obtained perpendicular magnetic recording medium, and the crystal structure of the comparative medium was examined. As a result, the Pd—Si first nonmagnetic underlayer was almost amorphous with no lattice fringes observed.

On the other hand, it was found that lattice stripes were regularly arranged from the Ru second nonmagnetic underlayer to the CoCrPt—SiO ₂ recording layer, and epitaxial growth occurred.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. . As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 8 to 13 nm.

  When the recording / reproduction characteristics were evaluated in the same manner as in Example 1, the SNRm was 18.1 dB.

Thereby, the medium of the present invention of Example 2 is more preferable than the conventional medium of Comparative Example 9.
It was found that the crystal grains of the perpendicular magnetic recording layer are fine and have good crystallinity and good recording / reproducing characteristics.

Example 3
A perpendicular magnetic recording medium was fabricated in the same manner as in Example 1 except that the nonmagnetic seed layer was formed using an Al-45 at% Si target instead of the Si target.

  The obtained perpendicular magnetic recording medium has the same configuration as the perpendicular magnetic recording medium shown in FIG. 2 except that an AlSi seed layer is formed instead of the Si seed layer.

  X-ray diffraction measurement was performed on the medium of the present invention.

  A Ru (00.2) peak and a CoCrPt (00.2) peak were observed, but a Pd (111) peak could not be observed. When rocking curve measurement was performed on these peaks, the half-widths of the peaks were 2.7 ° (Ru) and 3.4 ° (CoCrPt), respectively. Thereby, it was found that the perpendicular magnetic recording layer had good crystallinity.

  The obtained perpendicular magnetic recording medium was subjected to transmission analytical electron microscope (TEM) measurement in the cross-sectional direction to examine the crystal structure of the medium of the present invention. As a result, crystal lattice fringes were clearly observed in the first Pd nonmagnetic underlayer, but the direction was not uniform, and it was found that the Pd first nonmagnetic underlayer had a microcrystalline structure.

It was found that the Ru second nonmagnetic underlayer and the CoCrPt—SiO ₂ recording layer had crystal lattice stripes arranged in an orderly manner in the direction perpendicular to the film surface and were epitaxially grown from the second nonmagnetic underlayer to the recording layer.

  Next, transmission analytical electron microscope (TEM) measurement was performed on the perpendicular magnetic recording layer of the obtained perpendicular magnetic recording medium, and the particle size distribution of the crystal grains of the perpendicular magnetic recording layer of the medium of the present invention was examined. .

  As a result, it was found that the perpendicular magnetic recording layer was formed of crystal grains having an average grain size of about 4 to 7 nm.

  Further, when the recording / reproducing characteristics were evaluated in the same manner as in Example 1, it was found that the SNRm was 27.3 dB, and the characteristics were good.

Example 4
When the Si seed layer and the Pd first nonmagnetic underlayer of the medium of the present invention are formed, the gas pressure in the Ar atmosphere during DC magnetron sputtering is changed to various pressures of 0.05 Pa to 1.0 Pa. A perpendicular magnetic recording medium was manufactured in the same manner as in Example 1 except that the film was formed.

  The obtained perpendicular magnetic recording medium has the same configuration as the perpendicular magnetic recording medium shown in FIG. For the medium of the present invention, X-ray diffraction measurement and recording / reproduction characteristics were evaluated in the same manner as in Example 1. The full width at half maximum of the recording layer and the SNRm results are shown in Table 1 below.

  From the results of Table 1 above, it was found that when the seed layer and the first non-magnetic underlayer were produced at a pressure of 0.5 Pa or less, good characteristics were obtained. Practically, this pressure is preferably 0.05 Pa or more, and if it is less than 0.05 Pa, DC sputtering cannot be stably performed, which is not suitable.

Example 5
Instead of the Pd target as the first nonmagnetic underlayer, a target for laminating two Pd—Si layers having different compositions is used, and the Si seed layer is not used. Thus, a perpendicular magnetic recording medium was manufactured.

  The target for laminating two Pd—Si layers was a Pd-34 at% Si target on the soft magnetic side and a Pd-x at% Si target on the perpendicular magnetic recording layer side. Each of x was 3, 5, 7, 10, 13, 17, 20, 26, 34.

  The obtained perpendicular magnetic recording medium has a configuration similar to that of the perpendicular magnetic recording medium shown in FIG.

  X-ray diffraction measurement was performed on the obtained medium.

  Further, the recording / reproducing characteristics were evaluated in the same manner as in Example 1.

  Table 2 below shows the half width of the peak of the perpendicular magnetic recording layer and the SNRm result.

From the above, it was found that the medium of the present application has good characteristics when the Si content in the Pd—Si film is 3 to 10 at%.

Sectional drawing which represents typically the structure of the perpendicular magnetic recording medium which concerns on one Embodiment of this invention. Sectional drawing which represents typically the structure of the perpendicular magnetic recording medium which concerns on one Embodiment of this invention. 1 is a partially exploded perspective view of an example of a magnetic recording / reproducing apparatus of the present invention. Sectional drawing which represents typically the structure of the perpendicular magnetic recording medium which concerns on one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11 ... Nonmagnetic board | substrate, 2,12 ... Soft magnetic backing layer, 3,13 ... 1st nonmagnetic underlayer, 4,14 ... 2nd nonmagnetic underlayer, 5,15 ... Perpendicular magnetic recording layer, 6, 16 ... protective film, 7 ... bias applying layer, 8 ... nonmagnetic seed layer, 10, 20, 32, 50 ... perpendicular magnetic recording medium, 30 ... perpendicular magnetic recording device, 31 ... housing, 33 ... spindle motor, 34 ... Magnetic head, 35 ... Head actuator, 36 ... Rotating shaft, 37 ... Voice coil motor, 38 ... Head amplifier circuit

Claims (4)

Non-magnetic substrate,
At least one soft magnetic layer formed on a non-magnetic substrate;
Formed on the soft magnetic layer, having a fine crystal structure in which crystalline fine particles having a particle diameter of 1 to 3 nm are gathered, formed on the first Pd—Si layer and the first Pd—Si layer. A second Pd—Si layer having a Si content of less than 10 at%, wherein the Si content of the first Pd—Si layer is greater than the Si content of the second Pd—Si layer . A non-magnetic underlayer,
A second nonmagnetic underlayer made of ruthenium formed on the first nonmagnetic underlayer, and perpendicular magnetic recording containing Co and Pt as main components formed on the second nonmagnetic underlayer A perpendicular magnetic recording medium comprising a layer. The perpendicular magnetic recording medium of claim 1, the Si content of the first Pd-Si layer is characterized der Rukoto than 10at%. The perpendicular magnetic recording medium according to claim 1, a mechanism for supporting and rotating the perpendicular magnetic recording medium, an element for recording information on the perpendicular magnetic recording medium, and recorded information A magnetic recording / reproducing apparatus comprising: a magnetic head having an element for reproducing; and a carriage assembly that supports the magnetic head movably with respect to the perpendicular magnetic recording medium . As the recording head, a magnetic recording and reproducing apparatus according to claim 3, characterized in Rukoto that having a single-pole recording head.

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